In a typical electrical distribution system, an electrical supplier or utility company generates electrical energy and distributes the electrical energy to consumers via a power distribution network. The power distribution network is the network of electrical distribution wires which link the electrical supplier to its consumers. At the consumer's facility, there will typically be an electrical energy meter (revenue meter) connected between the consumer and the power distribution network to measure the consumer's electrical demand. The revenue meter is an electrical energy measurement device which accurately measures the amount of electrical energy flowing to the consumer from the supplier. The amount of electrical energy measured by the meter is then used to determine the amount required to compensate the energy supplier.
Typically, the electrical energy is delivered to the customers as an alternating current (“AC”) voltage that approximates a sine wave over a time period. The term “alternating waveform” generally describes any symmetrical waveform, including square, sawtooth, triangular, and sinusoidal waves, whose polarity varies regularly with time. The term “AC” (i.e., alternating current), however, almost always means that the current is produced from the application of a sinusoidal voltage, i.e., AC voltage. The expected frequency of the AC voltage, e.g., 50 Hertz (“Hz”), 60 Hz, or 400 Hz, is usually referred to as the “fundamental” frequency. Integer multiples of this fundamental frequency are usually referred to as harmonic frequencies.
While the fundamental frequency is the frequency that the electrical energy is expected to arrive with, various distribution system and environmental factors can distort the fundamental frequency, i.e., harmonic distortion, can cause spikes, surges, or sags, and can cause blackouts, brownouts, or other distribution system problems. These problems can greatly affect the quality of power received by the power customer at its facility or residence as well as make accurate determination of the actual energy delivered to the customer very difficult.
In order to solve these problems, socket based revenue meters have been developed to provide improved techniques for accurately measuring the amount of power used by the customer so that the customer is charged an appropriate amount and so that the utility company receives appropriate compensation for the power delivered and used by the customer.
To provide user input to the revenue meter, known meters typically utilize cumbersome keys or buttons located within a sealed cover of the revenue meter, or keys which are accessible from the outside but are sealed and cannot be activated without removing the seal. In both cases, at least one security seal is installed to prevent or indicate unauthorized access. Thus, the seal must be replaced every time the meter is accessed via the keys or buttons.
In addition, a problem exists when keys are added to the meter cover to mechanically actuate the interface of the revenue meter since tolerances in both the manufactured parts and the assembly process can cause an internal structure of the assembled revenue meter to misalign with the cover, for example, lean and twist with relation to the cover, resulting in misalignment of the mechanical actuators with the actual interface of the meter. Therefore, it is important to line up the keys/mechanical actuators on the cover with the appropriate buttons on the revenue meter.
Also, with the increasing complexity of revenue meters, usability has often been restricted by the user interface. Available systems permit the user to customize the data which can be viewed from the meter only with auxiliary devices. In available meters, a user can program the viewed data with an auxiliary device, such as a computer or calibration equipment. Such modifications often cannot be done easily in the field.
Accordingly, there is a need to provide a device with a user interface that allows the user to easily program various desired features for the device and provides a means to display various selected calculations and results generated by the meter.
In addition there is a need for an improved revenue meter that provides easily accessible and easy to use interfaces.